DE2425203A1 - FULLY AUTOMATIC GEAR WITH TORQUE CONVERTER - Google Patents

Description

Dipl.-Ing. H. MITSCHERLiCH D-8 MÖNCHEN 22 Dipl.-Ing. K. GUNSCHMANN TS ^ Hü

Dr. rer. not. W. KORBER ^V ™ Dipl.-Ing. J. SCHMIDT-EVERS May 24th PATENT LAWYERS

HANS IVAR REEIfSKOUG 2425203

63 Skogsgatan

S-582 57 Linköping. Sweden

Patent application

Fully automatic transmission with torque converter

The invention relates to an adjustable, fully automatic device in the form of a transmission that preferably intended for use in motor vehicles, but can also be used in other fields in cases in which it is desired to automatically output the speed of a power output shaft and the torque transmitted by it. to vary depending on the size of the load to be driven.

The device according to the invention has a torque converter of a known type, preferably a hydrodynamic one Torque converter, which works together with two or more mechanical gear stages, to which planetary gear stages that work as differential gears.

Some known constructions of this general type are constructed so that the full power of an engine is the hydrodynamic torque converter is supplied via a drive shaft, the torque converter providing the drive force transmits to a gear transmission with two or more gear stages, in which the relevant gear in which the desired gear ratio results, is engaged by a complicated automatic device that is adjustable is and determines the step-up or step-down ratio at which the power output shaft is driven.

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ORIGINAL INSPECTED

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The gears of this type known up to now are therefore of a complicated construction, often one of them only centrally located shaft is present, and because it is necessary, complicated automatic control devices to be provided. With this basic construction, the possibilities for further development are limited, and therefore are at Such transmissions only have two or three gears, although it would actually be desirable to add a fourth gear or even to have a fifth gear available.

. In another known type of automatic transmission, the torque converter is designed to drive the power output shaft drives parallel to a power transmission device with a mechanical gear of the planetary gear type, so that one works with a torque subdivision; in the case of gearboxes of this type, the required one is used in each case or required gear as well as the one described above known design selected with the help of a complicated hydraulic device, the pulses from a control device can be supplied, e.g. with the help of the accelerator pedal or a centrifugal governor arranged on the power output shaft. In the case of transmissions of this type, too, there is a centrally arranged shaft, which again requires a complicated one automatic control device, and the complexity of this device increases in a considerable Extent if additional gears or gear ratios are to be made available.

Although gears of the two types described above work properly if correctly constructed, they are liable Both types have a common disadvantage, which can be a nuisance under certain circumstances, e.g. on a slippery road surface makes noticeable. At the moment when a certain gear is engaged instead of another gear, a more or less strong perceptible shock, which usually becomes stronger the further the throttle of the engine is opened will. The fact that this cannot be avoided results from the fact that at the moment of gear change, rotating masses are accelerating.

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nigt or delayed, with lamellar or Band brakes are brought into effect.

Although gear changing devices are already known that work continuously and without jolts, the driving force is reduced with them transmitted by friction, or V-belt drives are used. Splche gears turn out to be in engines lower power than usable, but they are not suitable for high power engines and heavy vehicles.

The invention has now created a fully automatic transmission in which several mechanical transmission stages for the gear change are available, and in which the transition from one gear stage to another gear stage executes swiftly; here the construction of the transmission is so simple that it is possible to use a large number of gears one behind the other without causing a multiplication of the difficulties. The transmission according to the invention, which apparently works continuously, has known planetary gear sets serving for reduction and proven type, which make it possible to transfer full power even with high-performance engines and to take advantage of.

The fact that there are apparently no gear steps in the transmission according to the invention is due to that at the moment of shifting or changing gears neither in the gearbox nor in the engine Devices to be accelerated or decelerated need that the gear change takes place immediately, i.e. without Time consumption, and that the transmission of the drive torque of the engine neither when downshifting nor when upshifting interrupted even briefly. This way of working gives the driver of a motor vehicle, for example, the impression that that the engine is equipped with a continuously variable transmission.

The transmission according to the invention is essentially characterized in that a primary shaft of the transmission with one of the rotating parts, namely the turbine part of the rotating

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torque converter, as well as each with one of three rotatable Main facilities (two sun gears and one planet carrier) , which lead to several planetary gears arranged one behind the other belong, one of which is assigned to each gear of the transmission, cooperates; here is another rotatable main device of each planetary gear so arranged that it cooperates directly or via an overrunning clutch with the power output shaft of the transmission; Farther each of these planetary gears has a third main rotatable device which is arranged so that it cooperates directly or via a one-way clutch with a return shaft, which in turn works with a other rotatable part, namely the impeller, cooperates with the torque converter; here are the processes the transmission of motion and the gear change are carried out in such a way that that the impeller and the turbine part of the torque converter rotate in the same direction, and that in all occurring operating conditions, the speed of the blade or pump wheel is higher than the speed of the turbine part.

In order to improve the efficiency of the hydrodynamic torque converter, it may be useful to ensure that that the return shaft regulates the speed of the stator of the torque converter in the course of a gear change so that with different dimensions of the slip between the turbine wheel and the pump wheel an optimal cooperation of the Pump wheel is achieved with the turbine wheel.

In order to take into account the resistance forces that occur, it can be useful to place all overrunning clutches on the To arrange return wave, because the stress on this wave is less than the stress of the power output or Output shaft, so that there is also less stress on the overrunning clutches.

One embodiment of the invention which appears to be particularly expedient from a constructional point of view is essentially characterized in that all planetary gears are formed reciprocally identical, and that the

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three said main rotatable devices through each a large sun gear or a small sun gear can be formed, each with stored in a carrier Planetary gears cooperate, which forms the third main rotatable device; the big sun gear of every planetary gear is rotatably connected to the primary shaft of the gear, and the small sun gear of each planetary gear s is in constant mesh with a gear on the output shaft; the carrier of the planetary gears of all planetary gears are in constant mesh with an associated gear on the return shaft, and between each Planetary gear and the return shaft there is an overrunning clutch, so that the gear in question is the return shaft drives as soon as the transmission in question tries to overtake the return shaft.

It is in the nature of things that equivalent Solutions result if you make sure that the small sun gears with the return shaft and the planetary gear carriers cooperate with the power output shaft. Of course you can also use the overrunning clutches on the power output shaft order, but the overrunning clutches are in this case higher stresses for the reasons mentioned above exposed. To save space or for other reasons, it can be useful in certain cases to use a four-speed gearbox e.g. two overrunning clutches on the return shaft and two further overrunning clutches to arrange the output shaft. '

At each position for a specific gear the gear ratio is determined by the gear ratio between the gear on the output shaft and the associated one Drive wheel of the planetary gear determined.

The choice of the gear ratio between the gear on the return shaft and the associated gear of the Planetary gear determines which of the planetary gear is in engagement at a given moment and on the output shaft acts.

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Are the transmission ratios between the return wave and the planetary gear selected accordingly, is achieved according to the invention that by the slip of the Torque converter automatically that gear is selected that is suitable at the moment in question, with the overrunning clutches work together without the need for any additional automatic control equipment.

It is required when calculating the gear ratios from the specifications of the torque converter proceed or, in the opposite sense, proceed so that the slip in all gears is within the range of the torque converter is within which the efficiency is about $ 80 or more. Many known torque converters have exhibits a very flat curve of efficiency even with a relatively large slip, and it is important that all gear changes take place within this range.

The invention and advantageous details of the invention are shown below with reference to schematic drawings an exemplary embodiment explained in more detail.

1 to 3 show a longitudinal section or an enlarged partial section or a schematic end view a particularly useful, space-saving and simple embodiment of a transmission, with most bearings of clarity are shown for the sake of slide bearings, although in practice, of course, ball, roller or needle bearings are used would.

In Fig. 1 is an embodiment of a transmission according to the invention with a torque converter in longitudinal section shown. Fig. 2 shows an enlarged section through one of the reciprocally similar planetary gears, the is connected by an overrunning clutch to the return shaft of the transmission according to FIG. Fig. 3 shows a schematic Partial section along the line A-A in Fig. 1, from which the position of three cooperating gears can be seen is.

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The transmission shown includes three shafts, namely a primary shaft 1, a power output shaft 2 and one Return wave 3; one can say that the whole gear works as a differential gear at any given moment, that is, the force transmitted through the primary shaft 1 is divided between the output shaft 2 and the return shaft 3 in the same way as with a differential gear, which is used in a motor vehicle to distribute the drive force of the drive shaft to the "wheels to be driven".

The return shaft 3 is directly connected to the drive part, i.e. the pump wheel 4P, of the hydrodynamic Torque converter is coupled and the output part, i.e. the turbine wheel 4T, of the torque converter is rotatably connected to the primary shaft 1. The gear ratios are selected for all gears of the transmission so that that the pump wheel 4P always rotates at a higher speed than the turbine wheel 4T.

With this arrangement, the hydrodynamic torque converter exercises always a braking torque on the return shaft 3, and the size of this braking torque depends on the respective Slip between the impeller 4P and the turbine 4T. The presence of this on the return wave Acting braking torque is a prerequisite that a torque is applied to the output shaft 2, since the Planetary gears work as differential gears.

Since the torque converter is constantly striving to adjust so that the speed difference between the impeller 4P and the turbine wheel 4T becomes as small as the load to be driven allows, it causes the transmission to be automatic works in the highest possible gear, which is permitted by the existing slip. In other words, the lower the slip, the higher the gear with which the transmission works.

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It can thus be said that the above-mentioned braking torque that is applied to the return line shaft 3 is generated by the pump wheel 4P driven by the return shaft 3 which is that with the primary shaft 1 rotatably connected turbine wheel 4T drives, to which a force is thus transmitted, which by the in the relevant Planetary gear currently in operation has been branched off. This way of working makes it possible for dqm transmission or the gear shift device has a very high To achieve overall efficiency.

In the illustrated embodiment, the transmission has four gears, including four planetary gears of the same type 5, 6, 7 and 8 and four identical freewheel devices 9 »10, 11 and 12 that work together with them are assigned. Mg. 1 shows an embodiment in which all planetary gears are arranged on the primary shaft 1; this is an advantageous constructive measure that can be found in the Might work well in most cases. According to Mg. 1, all freewheels are arranged on the return shaft 3, so that a clear construction results. As mentioned, however, it can also be useful to have two of the freewheels on to arrange the power output shaft and the two remaining freewheels on the return shaft. In each of these cases it will be natural achieves the same effect.

The structure of the planetary gear 6 can be seen from Fig. 2, while the construction of the freewheel 10 is shown in FIG. The primary shaft 1 is non-rotatable with a Gear 13 connected, which forms the larger sun gear of the planetary gear 6 according to FIG. This larger sun gear 13 is constantly in engagement with two planet gears 14 and 15, which are rotatably mounted in a planet carrier 16. The planet carrier 16 is provided with a gear 17 or connected in a rotationally fixed manner, which is constantly in engagement with a gear 18 the output shaft 2 according to FIG. 1 is.

Each of the planet gears 14 and 15 is provided in a known manner with two toothings, one of which is in engagement

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is with the sun gear "13, which rotates with the primary shaft 1 is connected, while the other toothing meshes with the second sun gear 19 of the planetary gear 6, which on the hub of the sun gear 13 is rotatably mounted. At the hub of the sun gear 19 is shown in fig. 2 another gear 19a formed, which according to FIG. 2 is constantly in engagement with a gear 20 also visible in FIG. 1, the hub of which with of the return shaft 3 according to Mg. 1 as a freewheel device 10 cooperates, and which is provided in a known manner with rollers which have inclined grooves, not shown work together so that the shaft 3, when it rotates faster than the gear 20, with respect to this gear can rotate freely; However, as soon as the speed of the gear 20 reaches the speed of the return shaft 3, the freewheel device 10 is anchored to the gear compared to the return shaft, which means that now the gear 20 takes over the drive of the return shaft.

In the illustrated embodiment, the planetary gear carrier 16 is rotatably connected to it together with the Gear 17 rotatably mounted on the hub of the sun gear 19, in order to keep the overall length of the gearbox as small as possible. In Fig. 2 a reinforcement wall 23 can be seen, which extends through the transmission housing 22 in a manner which can also be seen from FIG. 1.

As mentioned, the freewheel devices are 9, 10, 11 and 12 of the same construction, but the gears which correspond to the gear 20 of the freewheel device 10, different dimensions.

Thus, the gear 20 and the corresponding gears of the other freewheel devices 10, 11 and 12 come to Effect that the return shaft 3 is driven by the gear wheel that has the highest speed running around.

The return shaft 3 drives the impeller 4P through with her non-rotatably connected gear 24 and a with the

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The pump wheel of the hydraulic torque converter is non-rotatably connected Gear 25 on.

Of particular importance for the invention and the mode of operation of the transmission to be achieved, however, is the fact that the return shaft 3 is constantly striving to the pump part 4P of the hydrodynamic torque converter on a Bring speed that is higher than the speed to which the turbine part 4-T is brought by the primary shaft 1.

To the operating conditions of the hydraulic torque converter and thus also to improve the overall efficiency, it may be useful to add another on the return shaft 3 To assemble gear 26, according to FIG. 3 via an intermediate gear 27, which is rotatably mounted on an axis 28 which is stationary with respect to the gear housing 22, and another Drive gear 29, which is rotatably connected to the blade part 30 of the hydraulic torque converter, which in turn, according to FIG. 1, is rotatably mounted on the primary shaft 1. With this arrangement, the blade part 30 is opposed the direction of rotation of the pump part 4P and the turbine part 4T.

The mode of operation of the transmission according to FIGS. 1 to 3 is explained in more detail below.

If the motor, not shown, is put into operation while the output shaft 2 is at a standstill or is braked, the primary shaft 1 begins to rotate at a low speed and the rotatably connected to it Turbine wheel to rotate 4T. This means that the freewheeling device 9 assigned to the starting process has the highest speed achieved, which can be attributed to the described selection of the transmission ratios for the drive gears, so that the energy taken from the planetary gear 5 coming into effect here is returned to the return shaft 3 and over the torque converter is returned to the primary shaft 1.

If the brake is released so that the output shaft 2 can start to rotate, the planetary gear 5 sets the

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Speed of the freewheel device 9 down, so that the Speed of the Rückleitungswelie 3 by the differential ■ gearbox coming into effect reduced planetary gear

will. ''

In the case of the other freewheel devices, the relevant speeds are also reduced, but at a lower rate Speed, and in the higher gears the speed is reduced ■ more slowly than in the lower gears, which in turn can be attributed to the described selection of the associated gear ratios for the various gears is.

When the speed of the output shaft 2 increases, the speed of the freewheeling device 9 therefore decreases more quickly than the speed of the freewheel device 10, which has the consequence that the freewheel device 10, so to speak, the freewheel device 9 catches up and finally in an almost unnoticeable way takes over the drive of the return shaft 3, which is now with rotates at a lower speed than before.

At the moment in which the freewheel device 10 takes over the drive of the return shaft 3, the second gear of the transmission is in operation, and if the speed the output shaft 2 increases with increasing speed of the vehicle, the third gear and possibly then another gear is brought into effect until the highest gear via the associated freewheel device to Effect comes.

As soon as the highest gear has been "engaged", the return shaft 3 rotates at its lowest speed.

If the rotation of the output shaft 2 is opposed to a greater resistance, so that a greater torque is required e.g. when driving on an uphill road, the speed of the output shaft decreases, and the speed of the return shaft 3 increases, so that the next lower freewheel device takes over the drive and the transmission works in its next lower gear.

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If the torque acting on the output shaft 2 is reduced again, the gearbox reacts to this, that it performs an upshift.

The torque converter is thus used to select the various slips that occur in each case Grange of the transmission. The greater the slip, the lower the gear selected.

As mentioned, the transmission described always strives to adjust so that the speed difference between the impeller 4P and the turbine 4T of the torque converter becomes as small as the load on the transmission allows. Thus, the transmission according to the invention always works in the highest gear, the one with a certain load is attainable. This mode of operation is achieved according to the invention without the need for any additional Control or regulating devices are to be provided.

Claims ;

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Claims (3)

-13- PATBNTAIISPSUCEE ' Fully automatic transmission of the type with a torque converter, preferably a hydrodynamic torque converter, which works together with two or more mechanical transmission gears, a planetary gear being provided for each transmission gear, characterized in that a primary shaft (1) of the transmission is connected to one of the rotatable parts of the torque converter, in particular the turbine part (4T), and in each case with one of the three main rotating parts, in particular the sun gear (13), several planetary gears (5, 6, 7-8) arranged one behind the other, of which one is assigned to each gear change, that several Overrunning clutches (9, 10, 11 and 12) are available, one of which is assigned to each gear change or each gear, that another rotatable main part, in particular the planetary gear carrier (16), each planetary gear is arranged so that it is directly or via the associated overrunning clutch (10) for the relevant Gear change cooperates either with the output shaft (2) of the gearbox or with a return shaft (3), which latter is set up so that it cooperates with another rotatable part, in particular the pump part (4P), of the torque converter, that the transmission of motion and the gear change is caused in each case so that the pump part and the turbine part of the torque converter rotate in the same direction, and that the pump part _{reaches a higher speed than the turbine part under Q} jlen occurring operating conditions, and that the third rotatable main part, in particular the sun gear (19) , each planetary gear transmission is set up so that it is either directly or via the associated overrunning clutch in the relevant gear. cooperates with the return shaft or with the output shaft of the gearbox. 409850/0920 2. Setriebe according to claim 1, characterized in that the return line (3) is a Gear (26) is rotatably connected that this gear is used to control the speed of a blade part (30) of the torque converter to bring to such a value that with different slip between the turbine wheel (4T) and the Pump wheel (4P) an optimal cooperation of the pump wheel with the turbine wheel is achieved, and that said gear wheel is in drive connection via an intermediate gear ″ (27) with a gear (29) which is connected to the paddle wheel of the torque converter is rotatably connected. 3. Transmission according to claim 1 and 2, characterized in that all planetary gear transmissions (5, 6, 7 and 8) are reciprocally similar, and that for the three mentioned main rotatable parts (13, 16 ^ 19) a larger sun gear (13) and a smaller sun gear (19) belong to the planetary gears mounted on a planet carrier (16) (14, 15) work together, the larger sun gear in each planetary gear transmission in a rotationally fixed manner with the Primary shaft (1) of the gearbox is connected and therefore rotates together with the primary shaft. attorney 409850/0920